Low pass filtering of electrical signals for removal of high frequency noise and disturbance signal content in noisy electronics environments, such as in automotive environments, is well-established. Low pass filter components may include such standard circuit components as capacitors and inductors arranged in a conventional Pi-filter configuration. The inductor filter component may be provided as a standard ferrite block through which conductive leads or pins may be driven to add series inductance to the leads or pins, which inductance may form the horizontal portion of the low-pass Pi-filter configuration. The vertical legs of the Pi-filter configuration may be provided as standard capacitors. Traditionally, such low pass filter components were installed on printed circuit boards, consuming precious board space. To free up printed circuit board space, such low pass filters have been integrated into header connectors which are attached to the printed circuit boards for interfacing printed circuit board input/output signals with wire harnesses. The wire harnesses may be attached, for example, to other electrical or electronics devices, such as sensors, actuator drivers, and electronics components of other printed circuit boards. The capacitors of such integrated low pass filters may be implemented as surface mount devices SMDs or discrete capacitor elements soldered to leads or conductive traces of a small printed circuit board substrate and assembled with the ferrite block into a plated plastic connector housing assembly. The housing assembly is installed in the header connector and electrically coupled to certain of the connector leads or pins requiring such low pass filtering.
Such conventional low pass filter mechanizations suffer shortcomings in the areas of cost, packaging and reliability. Discrete capacitor components are costly and consume significant connector space. Solder connections, required for both SMDs and discrete capacitor elements, add substantially to process costs, and are prone to cracking--especially under severe thermal cycling. For example, many header connectors can be cycled between such severe temperatures as -40 degrees Celsius and 125 degrees Celsius.
It would therefore be desirable to provide a solder-free, low cost and easily packaged low pass filter integrated into a header connector.